PTL 1 discloses a conventional loudspeaker which includes a frame, a magnetic circuit, and a diaphragm. The magnetic circuit is coupled to the frame.
The diaphragm includes a diaphragm body and an edge. The diaphragm body has a dome-shape. An outer circumference of the diaphragm is connected to the edge. An outer circumference of the edge is connected to the frame. The frame has a connecting surface. An outer circumference of the edge is connected to the connecting surface of the frame.
Another conventional loudspeaker includes a frame, a magnetic circuit, a support strut, a flat diaphragm, a first edge, a second edge, and a loudspeaker unit. The magnetic circuit is coupled to the frame. Threaded portions are formed on an upper end and a lower end of the support strut. The loudspeaker unit is mounted to the support strut and is fixed to the support strut with the threaded portion. The support strut is mounted to a center of the magnetic circuit, and is fixed to the magnetic circuit with the threaded portion.
An inner circumference of the first edge is coupled to an outer circumference of the diaphragm. On the other hand, an outer circumference of the first edge is coupled to the first frame. An outer circumference of the second edge is coupled to an inner circumference of the diaphragm. On the other hand, an inner circumference of the second edge is coupled to the loudspeaker unit.
A conventional loudspeaker similar to this loudspeaker is disclosed in, e.g. PTL 2.
FIG. 42 is a cross-sectional view of still another conventional loudspeaker 501 including conventional flat diaphragm 502. FIG. 43 is a top view of core substrate 502A of flat diaphragm 502.
Loudspeaker 501 is a coaxial-type loudspeaker. Loudspeaker 501 includes flat diaphragm 502 for reproducing low sound, high-frequency diaphragm 503 for reproducing sound in a high frequency band, voice coil 504, and voice coil bobbin 5 which transmits vibrations of voice coil 504 to flat diaphragm 502.
Although a position of a sound source can be unified with the use of flat diaphragm 502, flat diaphragm 502 exhibits fragility in mechanical strength because flat diaphragm 502 has a flat plate shape. To decrease fragility, flat diaphragm 502 includes core substrate 502A having high rigidity and skin layers 502B. Skin layers 502B is laminated on both surfaces of core substrate 502A with adhesive. A honeycomb structure shown in FIG. 43 is used in core substrate 502A, thus enhancing mechanical strength of flat diaphragm 502.
A loudspeaker similar to this loudspeaker is disclosed in, e.g. PTL 3. FIG. 44 is a cross-sectional view of another conventional loudspeaker 601. FIG. 45 is a cross-sectional view of flat diaphragm 602 of loudspeaker 601.
Although a position of a sound source can be unified with the use of flat diaphragm 602, flat diaphragm 602 exhibits fragility in mechanical strength because flat diaphragm 602 has a flat plate shape.
To decrease this mechanical fragility, flat diaphragm 602 includes core substrate 603 having a honeycomb structure and skin layers 604 mounted on both surfaces of core substrate 603.
In loudspeaker 601, in general, skin layer 604 made of, e.g. a thin aluminum plate is laminated on each surface of core substrate 603. Individual cells 607 of core substrate 603 are substantially sealed with skin layer 604 described above.
In such a configuration, flat diaphragm 602 is configured to receive vibrations of voice coil 605 via driver cone 606, thus reproducing sound.
A conventional loudspeaker similar to this loudspeaker is disclosed in, e.g. PTL 4. The loudspeaker including the flat diaphragm can stabilizes a distance between a power source and a listening position (ears) to a fixed value more easily than a loudspeaker including a cone diaphragm, hence reproducing sound with small distortion.
The conventional loudspeaker includes a magnetic circuit having a magnetic gap, a voice coil movably disposed in the magnetic gap of the magnetic circuit, a coupling cone fixed to the voice coil, and a flat diaphragm fixed to the coupling cone. One end of the coupling cone is fixed to the voice coil while another end of coupling cone is fixed to the flat diaphragm.
The coupling cone has a conical cylindrical shape such that the coupling cone has a small diameter on the voice coil and a large diameter on the flat diaphragm. A flange bent toward the outside is formed on a portion of the coupling cone toward the diaphragm. An adhesive which fixes the flange to a back-side plate body of the flat diaphragm is applied to the flange. A conventional loudspeaker similar to this loudspeaker is disclosed in PTL 5.